Seminario

Il giorno 13 febbraio alle ore 14,30 presso la stanza 412, il Prof. Sheldon Landsberger (Nuclear and Radiation Engineering Program Walker Department of Mechanical Engineering University of Texas at Austin, USA) terra' un seminario dal titolo

Coincidence and anti-coincidence gamma ray spectroscopy in radionuclide identification

Abstract

The two most challenging aspects of gamma ray spectrometry are to achieve spectral free interferences and to attain the lowest possible detection limits and ultimately low uncertainties. In nuclear forensics isotopic ratios or elemental ratios in environmental analyses need to have the individual results at low uncertainties for meaningful interpretations. Over the last decades gamma-gamma coincidence and anti-coincidence (Compton suppression) methods have been used for variety radionuclide identifications for passive counting of naturally occurring radioactive material (NORM), special nuclear materials (239Pu), fission products and neutron activation analysis (NAA) for environmental, geological, and biological samples. One real major advantage of these methods is that spectral interferences can be significantly reduced as in the case of Compton suppression or be eliminated as in gamma-gamma coincidence, while also reducing the Compton continuum and decreasing detection limits. For instance, the determination of 137Cs in soil with Compton suppression can be determined at less than 1 Bq/kg for only a twenty-gram sample. In neutron activation analysis elements such as arsenic and cadmium in biological specimens can be determined with detection limits at the ng/g level, which cannot be determined using traditional NAA methods. There are a host of elements determined by NAA that have benefitted using gamma-gamma coincidence and anti-coincidence methods. And in many cases, elements that are seldom or never reported, can now be effectively determined incorporating epithermal neutrons where the resonance integrals for several elements are high. An overview of these methods will be delineated with specific examples.

Zoom: https://cern.zoom.us/j/68713119184?pwd=HbCsVLUEbBC7JtpriZza6iUr5OylYN.1